Noise dissipation formula at DVinfo.net

Emre Safak · August 3rd, 2007, 01:24 PM

Is it possible to extrapolate the loudness in dB (A or C) of a source at some distance given its loudness nearby?

Jon Fairhurst · August 3rd, 2007, 03:02 PM

As I recall, sound drops off at the cube of the distance. It's the cube, because the sound waves spread out in three dimensions.

So, if you double the distance, the sound will fall off by a factor of eight (2^3), which is 9 dB (or is it 18 dB? I always get confused between power and amplitude.)

August 3rd, 2007, 01:24 PM	#1
Emre Safak Trustee Join Date: Feb 2004 Location: Brookline, MA Posts: 1,447	Noise dissipation formula Is it possible to extrapolate the loudness in dB (A or C) of a source at some distance given its loudness nearby?

August 3rd, 2007, 03:02 PM	#2
Jon Fairhurst Inner Circle Join Date: May 2006 Location: Camas, WA, USA Posts: 5,513	As I recall, sound drops off at the cube of the distance. It's the cube, because the sound waves spread out in three dimensions. So, if you double the distance, the sound will fall off by a factor of eight (2^3), which is 9 dB (or is it 18 dB? I always get confused between power and amplitude.) __________________ Jon Fairhurst